Data recording apparatus and system having sustained high transfer rates

ABSTRACT

According to the invention, techniques for recording data onto recording media at relatively high transfer rates for relatively long periods of time. Embodiments according to the present invention include systems and apparatus capable of an improved sustained rate of data recording onto disk type-recording media, for example. Many embodiments can remove the upper limits of both recording capacity and the number of media that can be used. Select embodiments can be used with different kinds of recording media as well. In a specific embodiment, the area on a hard disk is divided into three areas. A first area can be suitable for sequential recording of continuous data. A second area can be suitable for random recording of discontinuous data. A third area can be used for recording logical sector numbers, coupling logical sector numbers, and file information that are used for marking each of the first and second areas, so that continuous data can be recorded on the hard disk at a high data rate.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims priority from Japanese Patent ApplicationReference No. 11-074997, filed Mar. 19, 1999, the entire content ofwhich is incorporated herein by reference for all purposes.

BACKGROUND OF THE INVENTION

The present invention relates generally to disk type data recording, andspecifically to systems and apparatus used in reproducing digital media.

In recent years, many consumer-oriented products targeted to meeting arising consumer demand for recording information have become availableon the market. Data recording devices of many types now exist that canrecord data on various types of media. For example, hard disks can beprepared for use in personal computers (“PCs”) and magnetic recordingtape can be obtained for digital VTR, and the like. In particular, manytypes of storage media allow information stored thereon to be accessedat random, that is, the information need not be stored in any particularorder on the media. Other types of media are sequential. Sequentialmedia can provide quicker access to information stored thereon, but theinformation is stored in a sequential order on the medium. Further,digital information such as video and audio signals can be recreatedwith substantially the same quality as when recorded, even when therecordings are edited and copied repetitively. With such advantages,electronic storage media can provide many benefits to both commercialand business applications.

Applications may seek to store large amounts of information onto variousdigital media. While advantages to such applications can be readilyperceived, further efficiencies can be realized. In particular, thetechniques used to store information on various media can be improved toaccommodate applications that seek to store and retrieve large amountsof information from the media at suitable data rates.

What is really needed is an apparatus for recording relatively largeamounts of data onto disk type recording media.

SUMMARY OF THE INVENTION

According to the invention, techniques for recording data onto recordingmedia at relatively high transfer rates for relatively long periods oftime are provided. Embodiments according to the present inventioninclude systems and apparatus capable of an improved sustained rate ofdata recording onto disk type-recording media, for example. Manyembodiments can remove the upper limits of both recording capacity andthe number of media that can be used. Select embodiments can be usedwith different kinds of recording media as well.

In a representative embodiment according to the present invention, adata recording apparatus is provided. The recording apparatus canprovide a recording medium having a capacity that is to be divided intoat least a first area and a second area. Further, data received fromexternal sources can also be divided so that continuous data is recordedin the first area and discontinuous data is recorded in the second area,for example.

In a specific embodiment, the recording medium can further be providedwith a third area used to record management information of the datarecorded in the first and second areas. Continuous data can be bufferedone or more times before it is recorded in the first area. If the datain the buffer has reached a predetermined capacity, then the continuousdata can be copied from the buffer and recorded onto the recordingmedium. Data on the disk can be recorded into a plurality of recordingblocks disposed in tracks formed in a concentric circle pattern on adisk type-recording medium, for example.

In another specific embodiment, the first and second areas of therecording medium can comprise a plurality of recording sectors.Continuous data can be recorded sequentially in the recording sectorsdisposed in the first area, for example. The recording medium can be adisk type recording medium, or the like, in which case, each of theareas thereon can be divided along the radial direction of the disk. Ina particular embodiment, the first area can be disposed at the outermostperiphery of the medium. Data recorded in the first area can be copiedinto the second area, contemporaneously or at a later time. The numbersof the recording sectors in the first area in which the continuous datais recorded can be recorded in the third area, for tracking purposes andthe like.

In a further specific embodiment, faulty recording sectors on therecording medium can be detected and the numbers of the fault sectorscan be recorded in the third area. If continuous data is to be recordedin the first area, the data may be recorded by skipping such faultyrecording sectors. However, in select embodiments, the same data as thatin a block just positioned before a fault sector can be recorded in thefault sector so that the recording operation continues withoutinterruption.

In a yet further specific embodiment, cylinders that include one or morefault sectors can be recognized. Thus, a fault sector, or sectors,within a recording cylinder among concentric circle-like cylinders onthe disk type-recording medium can be detected and tracked. The numberof the recording cylinder containing the fault can be recorded in thethird area, for example. Data can be recorded continuously by skippingthe recording cylinder(s) having faults, enabling continuous recordingof data in the other cylinders.

Numerous benefits are achieved by way of the present invention overconventional techniques. The present invention can provide techniquesfor recording continuous data at relatively high transfer rates forrelatively long time periods onto a recording medium. The recordingmedium can be a disk-type recording medium, such as a hard disk or thelike. In some embodiments, the area on a hard disk can be divided intothree areas. The first area can be used for recording continuous datasequentially, the second area for recording discontinuous data atrandom, and the third area for recording logical numbers used formarking each of the first and second areas, as well as coupling sectornumbers and file information. Many such embodiments can recordcontinuous data on a hard disk at a high transfer rate so that the datacan be linked to other data managed by PCs and the like.

Some embodiments can be readily expanded. If additional recording mediaare employed, the first area or the second area can be secured invirtually any size on those additional media. Because neither a filemanager program nor an operating system (OS) program controls the firstarea directly, the number of hard disks that can be added isconceptually without limit. Many embodiments include hard disks that canbe suitable for recording video data from monitoring cameras, and thelike, for which a long time recording of audio-visual (“AV”) data isdesirable. Additionally, in some embodiments, data in both of thesequential recording (first) area and the random (second) recording areacan be read back at random, making it possible to handle a plurality ofdata types (continuous and discontinuous) concurrently in one datarecording apparatus. For example, it is possible to record dataendlessly in the sequential recording area and then copy the data fromthe endless recording area into another area, either contemporaneouslywhile the recording is being done, or at some time later.

These and other benefits are described throughout the presentspecification. A further understanding of the nature and advantages ofthe invention herein may be realized by reference to the remainingportions of the specification and the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified block diagram of a representative example datarecording apparatus in a particular embodiment according to the presentinvention;

FIG. 2 is a simplified diagram showing an example arrangement of datarecorded on a hard disk in a particular embodiment according to thepresent invention;

FIG. 3 is a simplified block diagram of a representative example datarecording apparatus in another particular embodiment according to thepresent invention;

FIG. 4 is a simplified diagram showing an example arrangement of datarecorded on a hard disk in a further particular embodiment according tothe present invention;

FIG. 5 is a simplified flowchart of a representative data copy operationfrom a first area into a second area in a particular embodimentaccording to the present invention;

FIG. 6 is a simplified diagram showing a representative arrangement forareas on a hard disk in a particular embodiment according to the presentinvention;

FIG. 7 is a simplified block diagram of a representative example datarecording apparatus in a still further particular embodiment accordingto the present invention;

FIG. 8 is a simplified diagram showing an example arrangement of datarecorded on a hard disk in a still further particular embodimentaccording to the present invention;

FIG. 9 is a simplified diagram showing an example arrangement of datarecorded on a hard disk in a still further particular embodimentaccording to the present invention; and

FIG. 10 is a simplified block diagram of a representative example datarecording apparatus in a yet still further particular embodimentaccording to the present invention.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

The present invention provides techniques for recording data on selectrecording media. Embodiments can record continuous data at relativelyhigh transfer rates for relatively long periods of time. Selectembodiments can record data onto disk type-recording media, and thelike. Embodiments according to the present invention include systems andapparatus capable of an improved sustained rate of data recording. Someembodiments can remove the upper limits of recording capacity, number ofmedia used, and kinds of media used.

Increasingly popular digital encoding techniques, such as MPEG2 (MovingPicture Experts Group 2) and MJPEG (Motion Joint Photographic codingExperts Group) have improved the quality of video and audio informationavailable to many applications. Along with the quality improvement ofvideo and audio signals, the amount of data to be handled has alsoincreased, creating strong demand for increased data throughput, i.e.,bytes to be transferred per second. In order to meet the demand of suchapplications, high capacity hard disks have been developed. For example,one commercial unit has a recording capacity of approximately 25 GB anda disk rotation speed of about 10,000 rpm. Such hard disks can also beprovided with interfaces capable of transferring data at a rate ofapproximately 33 MB/s, for example.

Furthermore, if video and audio digital information as described aboveare to be edited with sufficient quality using MPEG or MJPEG codingtechniques, a transfer rate that allows for continued recording orreading back on/from the recording becomes desirable. In other words,the sustained rate that a disk type storage medium can be used in aparticular application becomes an important characteristic. The transferrate typically described in the specifications of hard disks at presentis typically a maximum transfer rate between hard disk interface and aPC interface. For example, a particular disk may have a maximum transferrate of about 33 MB/s. The sustained rate, however, is determinedaccording to the recording density, the disk rotation speed, and thehead seek speed of the hard disk. For example, in a low-end hard disk,the actual transfer rate can be about 12 to 17 MB/s, for example. Inaddition, sometimes files can be managed on a hard disk in recordingblocks (“sectors”). Sectors can be recorded at random places on a diskby a file manager program installed in the PC, for example. Sometimes,discontinuous empty sectors can become scattered on the disk as a resultof repetitive erasure and addition of files. Consequently, if continuousdata is to be recorded on a hard disk, the head of the hard disk seeksthe scattered empty sectors sequentially during the data recording,which can lead to lower sustained data rates, thereby disabling highrate recording of continuous data.

A PC can manage data files on a hard disk using a file manager programor an operating system program (“OS”), for example. The hard diskcapacity that can be handled in the PC and the number of hard disks thatcan be used with the program can be limited by the specifications of thefile manager program or the OS. For example, if a file manager programconforms to FAT16, the capacity per partition can be limited toapproximately 2 GB and the number of additional hard disks may belimited to approximately 26, in a representative embodiment. The maximumrecording capacity of the hard disk unit will thus be approximately 52GB in this representative example. Consequently, such a particular filemanager program would not be used to record data on a 100 GB hard diskunit, for example.

Disk type recording media can provide random access and fastrecording/reading back of data, for example. Conventionally, hard disksinstalled in PCs can be used to write and read data or filesrespectively and repetitively. Thus, fragmentary problems that arisefrom such hard disks are not as serious in many conventionalembodiments. For example, a fragmentary problem could arise in anexample case where approximately 1000 files of approximately 32 KB insize are written on a hard disk. Then 300 of the 1000 files (capacity:9600 KB) are erased at random after the writing. The hard disk in thisstate will have scattered discontinuous empty areas thereon. If a fileof approximately 9600 KB in size is recorded on the hard disk just afterthe erasing, the file manager program can then record the 9600 KB filewithin the scattered empty areas. Consequently, searching, recording,and verifying operations are repeated for those scattered empty areas asneeded on the hard disk. Such operations can lower the throughput of thehard disk.

If data to be recorded/read back on/from a hard disk is a single shortfile, data, or an application program to be handled within a PC, forexample, such a fragmentary problem will not become serious. However,applications in which video or audio signals (“AV signals”) areconverted to continuous digital data that is recorded/read back on/froma hard disk, conventional file management techniques typically do notprovide data throughput because the overhead becomes too large. AVsignal data, such as an MPEG stream, for example, requires a sustainedrate of about 10 Mbps. In addition, if a plurality of data types(continuous and discontinuous) is to be handled thereafter, thesustained rate can be increased.

One technique for reading/writing comparatively large files from/on harddisks can read data in ascending or descending order of access sectornumbers from those hard disks provided with memory, respectively. Thistechnique is intended to minimize the number of seek operations forreading a data file. Further details regarding operation of hard diskdrive units employing such techniques can be had by reference to aJapanese Patent Application No. 10-63432, the entire contents of whichare incorporated herein by reference for all purposes.

FIG. 1 is a simplified block diagram of a representative example datarecording apparatus in a particular embodiment according to the presentinvention. This diagram is merely an illustration and should not limitthe scope of the claims herein. One of ordinary skill in the art wouldrecognize other variations, modifications, and alternatives. FIG. 1illustrates a block diagram of a disk type recording/reading apparatusin a representative embodiment according to the present invention. Dataentered from digital stream input terminal 11 is transferred to adigital signal input circuit 12. The data to be processed in thisembodiment comprises digital data, which can be a result of compressingAV signals using MJPEG coding, and the like. In some embodiments, thedata can be continuous data transferred at a high rate. In someembodiments, the MJPEG coding may be replaced with other imagecompression coding.

The digital input processor 12 adds delimiter information to each frameof input video data so as to divide the data into data blocks of apredetermined size. The divided data can be stored in a WR buffer 13,for example. The WR buffer 13 comprises, for example, a semiconductormemory and can be used to store data entered from the digital signalinput circuit 12. The data can be stored sequentially in an exampleembodiment. When a predetermined capacity for WR buffer 13 is reached,the data stored in the WR buffer 13, can be entered sequentially to adisk I/O protocol circuit 14 via the digital signal input circuit 12,for example.

In a representative embodiment according to the present invention, thedisk I/O protocol circuit 14 operates according to a data protocolconforming to the IDE interface used generally for disk-type storage.However, in other embodiments, the disk I/O protocol circuit 14 may useother protocols, such as for example, SCSI, USB, IEEE1394 standards, andthe like. The disk I/O protocol circuit 14 handshakes with the objecthard disk 1 to transfer data to the disk interface 9 in units of 512bytes, which is the minimum recording block (“sector”) of the hard disk1, in this embodiment.

FIG. 1 further illustrates a mechanism 10 of hard disk 1 in a specificembodiment. Hard disk mechanism 10 comprises a plurality of disks 1rotated by a spindle motor 4 (“SPM”). In a representative embodiment,each of the disks is attached to the shaft of SPM 4. Each of the disks 1can comprise a glass disc formed by magnetic evaporation, for example. Ahead 2 is mounted for each side of each of the disks 1. The head 2 isdriven in the radial direction of the disk 1 by a voice coil motor 6(“VCM”) so as to record/read back data on/from sectors that can bedisposed on the disk in a concentric circle pattern, for example.

The SPM driver 5 controls the rotation speed of the SPM 4. The VCMdriver 7 drives the VCM 6 so as to control the position of the head 2 inthe radial direction of the disk 1 so as to move the head 2 to theposition of a particular sector. The controller 8 controls the drivingof both VCM driver 7 and SPM driver 5 according to the recordingposition information from the disk interface 9, for example. The RD/WRsignal processor 3 can modulate/demodulate signals to record/read backdata on/from the disk 1 via the head 2, as well as correct data errors.

In a representative embodiment according to the present invention,sectors are disposed in a concentric circle pattern on each of aplurality of disks 1. In a representative embodiment according to thepresent invention, hard disks can have a storage capacity ofapproximately 6.4 GB, for example. In a specific embodiment, a hard diskunit can have on the order of eight logical disks 1 (one of the eightdisks allows data to be recorded/read on/from only one side, in thisembodiment, however). A logical recording/reading head 2 is provided toeach side of each disk 1, so a total of 15 heads 2 is provided in aspecific embodiment. Approximately 13320 logical sectors (to be referredto as logical cylinders hereafter) can be formed in a concentric circlepattern on each side of each disk. Some 63 logical sectors can be formedin a cylinder. In a specific embodiment, the recording capacity persector can be approximately 512 bytes. The recording capacity of arepresentative hard disk unit in a particular embodiment can becalculated as follows:512(bytes)×63(sectors)×13320(cylinders)×15(heads)=6444748800 bytes  (1)

The number of sectors of the whole hard disk unit is calculated asfollows:63(sectors)×13320(cylinders)×15(heads)=12587400(sectors)  (2)

In a representative embodiment according to the present invention,logical sectors can be specified uniquely by three items: a head number,such as, for example 1 to 15, a cylinder number 0 to 13319, for example,and a sector number, such as, for example 1 to 63. A target sectoraccessed according to the specification of the head number, the cylindernumber, and the sector number as described above is referred to as aphysical sector. A serial number is given to each of the sectors foundin the above expression 2, so that those sectors are handled ascontinuity sectors. Such sectors are referred to as logical sectors.Those logical sectors can also be numbered freely on each disk. Forexample, the fifteen sides of the disks 1 are numbered so as to be usedin parallel starting at the outermost periphery, thereby the movingdistance of the head 2 can be minimized. As a result, each disk can beswitched to another for accessing. In such embodiments, a logical sectornumber is calculated according to the following relation:LSN=SPT×(HEN+NOS×CYN)+SEN−1  (3)

where LSN is a logical sector number, SEN is a sector number, CYN is acylinder number, HEN is a head number, the number of sectors in acylinder is SPT, and the total number of heads is NOS.

The numbering of logical sectors in the embodiments described above canbe well suited for recording/reading back continuous data, for example.Although the (expression 3) is used for numbering the logical sectors onthe disks in a hard disk unit, such numbering may also be made forlogical sectors on a specified disk. Alternatively, a plurality ofnumbering systems may be prepared for logical sectors, in variousembodiments according to the present invention.

Data read from a hard disk can be entered to the disk I/O protocolcircuit 14 via the disk interface 9 according to the disk's I/Oprotocol. Continuous data read from the disk I/O protocol circuit 14 canbe divided into data blocks having a predetermined length according to adelimiter information, then stored in an RD buffer 16 temporarily. TheRD buffer 16 can comprise, for example, a semiconductor memory and canstore sequential data, and the like. The data stored in the RD buffer 16can be output from a digital output terminal 17 when the data reaches apredetermined amount, for example.

In a representative embodiment according to the present invention, datacan be recorded and read back in/from hard disks in units of sectors(512 bytes, for example) as described above. However, when continuousdata is stored in a WR buffer using units of sectors, or the data isrecorded in the disk I/O protocol circuit 14 using units of sectors, theoverhead can become large. Overhead can arise due to the specificationof the head number, the cylinder number, and the sector number for eachof the sectors, as well as the head seek operation of the disk mechanism10. Thus, such schema can become inconvenient for accessing continuousdata. Therefore, in a representative embodiment according to the presentinvention, data can be recorded/read back on/from a hard disk inportions appropriate to continuous data. Such embodiments can maintain amaximum sustained rate of data access to a hard disk, for example.

In a representative embodiment according to the present invention,therefore, continuous data can be recorded/read back on/from a hard diskin units of cylinders. Accessing a hard disk in cylinders, the overheaddue to rotational delay of the disk when accessing a single sector canbe avoided, thereby reducing the overhead of the disk access to thedelay due to a moving distance of the head in the radial direction ofthe disk. Higher data transfer rates, such as for example 10 Mbps ormore, can be achieved by controlling the record/read back of data usinga plurality of cylinders collectively. Accordingly, throughput of thehard disk can be maximized in representative embodiments.

In specific embodiments, minimum capacities of RD buffer 16 and WRbuffer 13 can be determined in order to enable accessing the hard diskin units of cylinders. For example, a 6.4 GB hard disk having 63 sectorsper cylinder that is to be accessed in units of 30 cylinders, wouldrequire at least a 967680-byte RD buffer 16 and a 967680-byte WR buffer13. Since memory is typically unavailable in fractional capacities, soeach buffer can be realized using a 1 MB memory, for example.

In a representative embodiment according to the present invention, diskarea can be divided to accommodate access in units of cylinders. Datacan be written/read back on/from a hard disk intermittently andrepetitively in each cluster of the disk. Clusters can comprise of aplurality of logical sectors, such as for example, 4 sectors/cluster ina PC based file manager program. Thus, the rate that clusters arefragmented can be increased when the disk is accessed in units ofcylinders, causing the sustained data access rate of the hard disk to bereduced. In a representative embodiment according to the presentinvention, data can be recorded on a hard disk continuously at itsmaximum sustained rate, by recording the consecutive logical sectornumbers described above sequentially. In addition, the head movingdistance for disk access can be managed to approximately one-cylinderdistance, which is the minimum limit in the magnetic disk radialdirection.

In a representative embodiment according to the present invention, therecording area of one or more hard disks can be divided into a pluralityof areas. For example, in a specific embodiment three areas can beprovided for record/read back of continuous data. In a specificembodiment, a first area for recording/reading back continuous data isprovided. Further, a second area for recording/reading back single(discontinuous) data according to the file management methods employedin conventional PCs, can also be included. Yet further, a third area forrecording management information of both continuous data and single(discontinuous) data can be provided.

FIG. 2 is a simplified diagram showing an example arrangement of datarecorded on a hard disk in a particular embodiment according to thepresent invention. This diagram is merely an illustration and should notlimit the scope of the claims herein. One of ordinary skill in the artwould recognize other variations, modifications, and alternatives. FIG.2 illustrates a representative internal structure of a hard disk, whichis divided into three areas; a first area, a second area, and a thirdarea. As shown in FIG. 2, the area 30 in the hard disk comprises of thethird area 38, the second area 39, and the first area 40. In the thirdarea 38, a FAT 31 is provided. However, it is noteworthy that specificembodiments according to the present invention can be realized usingother types of file management programs. FAT 31 is a table area formanaging files on the hard disk 30. The FAT 31 comprises an area 32 forrecording a file name group of continuous data or single (discontinuous)file data recorded on the hard disk. Further, FAT 31 comprises an area33 for recording file attributes, an area 34 for recording a time stampfor each file, and an area 35 for recording logical sector numbersanalogous to indexes of continuous logical sectors. Data is recorded inthe first area 40 and the second area 39. The data recorded in areas 40and 39 can have its own characteristics respectively.

In first area 40, continuous data can be recorded sequentially in thesectors. Partial sector writing and erasures are not permitted to thelogical sectors of first area 40 in a representative embodimentaccording to the present invention. In FIG. 2, the dark portions in thefirst area 40 represent portions having data recorded thereon. The firstarea 40 can be dedicated to recording of continuous data. Suchcontinuous data can comprise such digital data as AV, and the like.Logical sector numbers for starting points, ending points, or indexpoints of data recorded in area 40 can be stored in logical sectornumber manager table 27 in FIG. 1, for example.

If a signal for selecting read-back of specified data is entered from anoperation circuit 18 in FIG. 1, a disk center controller 19 can read thelogical sector of the selected data from the logical sector numbermanager table 27. Then, continuity sector controller 25 can specify alogical sector in the first area 40 of the hard disk 36 at random, sothat the data is read back from the sector. If the logical sectorcontroller 20 accesses logical sectors sequentially while recording,then a physical sector controller 21 can specify each logical sector andcan determine the head number, the cylinder number, and the sectornumber, for example, for the target physical sector. Then those itemscan be entered into the disk I/O protocol circuit 14. The head 2 of thedisk mechanism 10 can then be positioned at the target sector so thatdata can be written or read back in/from the sector.

In a representative embodiment according to the present invention, firstarea 40 in the hard disk can be used for recording continuous AV data inmonitoring applications, for example. For embodiments employed inmonitoring system applications, it can be desirable to record both videoand audio data for relatively lengthy periods of time. In suchembodiments, upon occurrence of an event of interest, such as, forexample, when an alarm is issued, it becomes desirable to record bothvideo and audio data continuously at that time. Continuous AV data froma monitoring camera, for example, can be recorded in the first area 40of the hard disk. In a specific embodiment, when an alarm is issued,each logical sector number can be stored in sector number manager table27. The disk center controller 19 can perform an alarm search or apriority search by alarm level. At a later time, the searched alarmpoint can be specified, thereby specifying the logical sectors in thefirst area 40 from which data can be read back from at random. Iflogical sectors in a hard disk (in the first area 40) with a limitedcapacity are specified endlessly, an endless recording can be made. Inthis embodiment, data recorded in logical sectors in the first area 40in a predetermined section after an alarm is issued can be read backfrom the logical sectors in the first area 40 and then can be copiedinto the second area 39 of the hard disk 2. As a result, the AV datacorresponding to the issued alarm in the first area can be saved.

FIG. 5 is a simplified flowchart of a representative data copy operationfrom a first area into a second area in a particular embodimentaccording to the present invention. This diagram is merely anillustration and should not limit the scope of the claims herein. One ofordinary skill in the art would recognize other variations,modifications, and alternatives. FIG. 5 illustrates processing for arepresentative embodiment in a monitoring application, such as the onedescribed above. In FIG. 5, processing begins with an ENTRY step 60. Ina step 61, continuous data can be recorded endlessly in the first area40 of the hard disk 1. In a step 62, based upon an entered command, itcan be determined whether to hold the data in a predetermined range inthe first area 40. If no partial data is to be held in step 62, controlreturns to step 61. If partial data is to be held in step 62, controlcontinues with a step 63. In step 63, both start and end logical sectornumbers of the first area 40 can be read back. The start and end logicalnumbers indicate the range of the data held in step 62. Then, in a step64, data is read back from both start and end logical sectors in thefirst area 40 in parallel to the endless recording in the first area 40.The read data can be recorded in the second area 39, for example. Thecopy operation from the first area 40 to the second area 39 can becontinued up to the end sector number. In addition, the endlessrecording in the first area 40 need not be stopped by the copyoperation. Rather, the recording can be continued according to thepriority given to the operation over the copy operation. The hard diskthat can handle a plurality of data types (continuous and discontinuous)in different operations at the same time as described above isespecially suitable for such monitoring embodiments that continuerecording nonstop.

In a representative embodiment according to the present invention, ahard disk can include a first area, in which a plurality of data types(continuous and discontinuous) can be stored and read back. Referringagain to FIG. 1, WR buffer 13 and the RD buffer 16 can be configured tomeet such requirements. While data is recorded on the hard disk, theread-back data stored in the RD buffer is output. While data is readback from the hard disk, data is stored in the WR buffer 13. Forexample, in a specific embodiment, data can be recorded in the firstarea in the hard disk at a data rate of, for example, approximately 6Mbps. Approximately contemporaneously, data can be read back from thefirst area at a data rate of, for example, approximately 6 Mbps. Analarm sector number can be recorded in a specified sector in the firstarea at a data rate of, for example, approximately 6 Mbps, and thesustained data rate of the hard disk can be for example, approximately40 Mbps. In this specific embodiment, data can be written/read backon/from the hard disk at a rate higher than the total of the multipledata rates at the same time. A particular embodiment can carry out bothrecording and reading back operations under such conditions even when anoverhead that includes both head seek time and timing delay time exists.

FIG. 2 illustrates second area 39 of a hard disk. In second area 39,files can be managed according to random access techniques, such asthose employed in Personal Computer file systems. In this second area,data can be recorded and erased at random, for example. FIG. 2illustrates a dark portion within the second area 39, representingportions of second area 39 having data recorded therein. In this secondarea 39, single (discontinuous) data can be recorded in a random or“scattered” manner. In this area, fragments can be generated. Data to berecorded in this second area can be recorded in a scattered and/ordivided arrangement within the second area. Consequently, both sectorcoupling state and directory hierarchical structure information can bemanaged by a file manager 22 illustrated in FIG. 1 and stored in thefile manager table 24. In a representative embodiment according to thepresent invention, the area on a magnetic recording disk can be dividedinto the first to third areas in the radial direction. In particular,the first area that provides a sustained data rate can be disposed atthe outer portion of the disk. FIG. 6 shows an image of the disk areadivided as described above.

FIG. 6 is a simplified diagram showing a representative arrangement forareas on a hard disk in a particular embodiment according to the presentinvention. This diagram is merely an illustration and should not limitthe scope of the claims herein. One of ordinary skill in the art wouldrecognize other variations, modifications, and alternatives. In FIG. 6,the area on each of disks 69 to 71 can be divided into a first area 66,a third area 67, and a second area 68, for example. Data in these areascan be read back by a head 75 moved by the corresponding one of the headseek arms 72 to 74, for example. In a specific embodiment, a 3.5-inchhard disk can have a radius of a recording side of the magneticrecording disk of about 4.5 cm maximum and about 2.0 cm minimum, forexample. The number of sectors per cylinder can be approximatelyproportionate to the radius of the disk. Consequently, the sustainedrate can increase as the outer part of the cylinder is approached. Forexample, in a representative embodiment, for a 3.5-inch hard disk thatrotates at approximately 5400 rpm, the sustained rate is approximately 3MB/s at the outermost portion and approximately 1.5 MB/s at theinnermost portion. If the first area for recording continuous data canbe disposed near to an area where a maximum sustained rate can beprovided; the throughput of data can be increased.

In a representative embodiment according to the present invention, thefirst and second areas can be configured by entering operation commandsfor the hard disk that is in the initial status (no-recorded status)from the operation circuit 18. The operation commands can specify thecapacities of the first and second areas, and the like. The disk centercontroller 19 recognizes the operation commands and a file space setupcircuit 23 and a continuity sector space setup circuit 26 can obtain thelogical sector numbers of the hard disk for each of the areas. Thisprocess to divide the hard disk area can occur under the control of thedisk center controller 19.

The data from the file manager table 24 and the continuous logicalsector number manager table 27 can be recorded in the third area 38 ofthe hard disk, for example. In a particular embodiment, the managementinformation, when read from the hard disk, can be stored in the filemanager table 24 and the continuous logical sector number manager table27 temporarily, so that the management information in the third area 38can be updated at predetermined intervals. The third area 38 stores, forexample, each file name 32, the file attribute 33, a time stamp 34, acontinuous logical sector number 35, directory hierarchical structureinformation 36, user information 37, and the like. In addition, any ofthe first, second, and third areas on the hard disk for recording datacan be specified from the operation circuit 18. For example, it can bespecified so that continuous AV data, having a data rate ofapproximately 30 frames/sec, for example, can be recorded in the firstarea and still picture data can be recorded in the second area. Both AVand still picture data can also be recorded in any same area. However,because the data recorded in the first area is sequential data, thisdata can be read back and recovered easily when, for example, the thirdarea is damaged due to a hard disk failure or a partial damage occurs inthe FAT information.

Specific embodiments according to the present invention provide fordividing an area of a hard disk into a sequential recording area, arandom recording area, and another area for recording logical sectornumbers. The sequential recording area is suitable for recordingcontinuous data, for example. The random recording area is suited torecording discontinuous data, and the like. The third area can be usefulfor recording logical sector numbers, coupling logical sector numbers,file information, and the like, that can be used for marking each of thesequential and random recording areas. Continuous data can be recordedat a high rate in specific embodiments so as to be linked with the datamanaged by conventional PCs. In a specific embodiment, a data recordingapparatus suitable for recording data, such as video or audio data frommonitoring cameras, is provided. Such embodiments can record such datasequentially in logical sectors endlessly, for example. Further, manyembodiments can copy the data from the endless recording area into otherareas on the hard disk during the recording, thereby managing recordingof a plurality of heterogeneous data types (continuous anddiscontinuous) at the same time in a single apparatus.

Next, another embodiment according to the present invention will bedescribed with reference to FIG. 3. FIG. 3 illustrates a simplifiedblock diagram of a representative embodiment of a data recording havingone or more additional hard disks. While operation of the embodimentsillustrated by FIG. 3 is described generally using an example having anIDE interface, the interface may be another type. For example,embodiments employing any of a SCSI interface, a USB interface, anIEEE1394 interface, and the like can be readily realized by those ofordinary skill in the art.

FIG. 3 is a simplified block diagram of a representative example datarecording apparatus in another particular embodiment according to thepresent invention. This diagram is merely an illustration and should notlimit the scope of the claims herein. One of ordinary skill in the artwould recognize other variations, modifications, and alternatives. Theembodiment illustrated in FIG. 3 comprises a hard disk mechanism 10 aand a hard disk controller 50, which controls mechanism 10 a, as well asmany functional blocks discussed previously with reference to FIG. 1.

Embodiments comprising hard disks having relatively larger capacitiescan record such digital data as audiovisual data, and the like arereadily achievable by those of ordinary skill in the art. For example,in one representative embodiment, approximately 10 M bps of MJPEG formatdata can be recorded in a hard disk having a capacity of approximately6.4 GB in about 85 minutes. Embodiments employing disk divisiontechniques according to the present invention can further shorten therecording time. In a representative embodiment according to the presentinvention, employing one or more additional hard disks can expand thefirst area suitable for recording continuous data. Adding hard disks canbe performed in a variety of ways to form a variety of specificembodiments. For example, in a PC that employs an IDE format hard disk,the PC can typically be provided with approximately four additional harddisk bays. If the PC is equipped with a SCSI interface, then it canconnect up to approximately seven hard disks per each SCSI interface,for example.

It is noteworthy that, in some embodiments according to the presentinvention, because the first area is not under the direct control of afile manager program and associated OS control programs, there isvirtually no limit to the number of additional hard disks and thecapacity per hard disk. Thus, embodiments according to the presentinvention are unlike conventional systems. Systems and methods using thetechniques of the present invention do not suffer limitations associatedwith many conventional recordation techniques.

In a representative embodiment according to the present invention,branch controller 50 in FIG. 3 can be provided with, for example, aplurality of IDE interfaces having different addresses. Thus, thecontinuity sector space setup circuit 26 can set up the third area inthe integrated area of the hard disks in the additional disk mechanism10 a to follow the logical sector numbers corresponding to the firstarea of the hard disk in the disk mechanism 10. In this way, logicalsector numbers can be assigned for controlling. The disk I/O protocolcircuit 14 operates the switching between addresses of the IDEinterfaces following the logical sector numbers corresponding to thethird area.

FIG. 4 is a simplified diagram showing an example arrangement of datarecorded on a hard disk in a further particular embodiment according tothe present invention. This diagram is merely an illustration and shouldnot limit the scope of the claims herein. One of ordinary skill in theart would recognize other variations, modifications, and alternatives.FIG. 4 shows how the areas of the recording media can be divided in thedisk mechanisms 10 and 10 a of FIG. 3, for example. In FIG. 4, therecording medium 30 comprises a recording area in the disk mechanism 10.The recording medium 51 comprises a recording area in the disk mechanism10 a. In a representative embodiment, the area of recording medium 51can be used as the first area, for example. Internally, the disk ofrecording medium 51 can comprise continuous logical block numbers thatcan be accessed so that continuous data can be recorded in the blockssequentially according to logical sector block numbers, for example.

In a representative embodiment according to the present invention, thefirst area suitable for recording continuous data can be expanded toadditional hard disks, for example. Because the file management programand the OS do not control the first area directly, there is noconceptual limit to the number of additional hard disks or the capacityper hard disk. Many embodiments are suitable for recording data inmonitoring cameras, and the like, that record AV data for relativelylong periods of time. For example, in one representative embodiment,about four hard disks of approximately 25 GB in capacity can beconnected to receive video data at a rate of about 2 frames/sec for upto one month or more.

Next, still further embodiments according to the present invention willbe described with reference to FIG. 7.

FIG. 7 is a simplified block diagram of a representative example datarecording apparatus in a still further particular embodiment accordingto the present invention. This diagram is merely an illustration andshould not limit the scope of the claims herein. One of ordinary skillin the art would recognize other variations, modifications, andalternatives. The specific embodiment illustrated in FIG. 7 comprises atest data generator 80, a full sector RD/WR tester 81, and a faultsector number checker 82, as well as many functional blocks previouslydiscussed with reference to FIG. 1. In specific embodiments, recordingcan be controlled so that sectors disabled for recording or reading back(“fault sectors”) are detected in the first area for recordingcontinuous data and those fault sectors are not used.

The operation circuit 18 processes a command for checking a fault sectorin the first area on a magnetic recording disk. Then full sector RD/WRtester 81 can record the test data generated in the test data generator80 in the specified sector, and then verify the recording operation. Ifthe recorded data does not match the test data in the verify operation,the verify operation can be repeated a specified number of times. Thenumber of the sector determined to be unusable by tester 81 can bestored in a fault sector number setup circuit 82. The stored faultsector number can be stored in the third area of the disk together withthe data stored in the file manager table 24 and the sector numbermanager table 27.

FIG. 8 is a simplified diagram showing an example arrangement of datarecorded on a hard disk in a still further particular embodimentaccording to the present invention. This diagram is merely anillustration and should not limit the scope of the claims herein. One ofordinary skill in the art would recognize other variations,modifications, and alternatives. In FIG. 8, there are fault sectors 83to 85 in the first area 40 of a hard disk. The fault sector informationfield 86 can store fault sector numbers 83 to 85, representing the faultsectors in the first area 40 of the hard disk. When recording continuousdata, the data recording apparatus that assigns numbers to logicalsectors can skip the fault sectors.

When data is record in logical sectors, the sectors can be specified sothat fault sectors 83 to 85 are skipped. In other words, the physicalsector controller 21 in FIG. 7 can assure that the head number, thecylinder number, and the sector numbers are transmitted to the disk I/Oprotocol circuit 14 so as to avoid accessing the fault sectors 83 to 85.Consequently, when the head reaches one of the fault sectors (83-85),the recording can be stopped temporarily, then a record command can betransmitted to the disk I/O protocol circuit 14 so as to restart therecording at a sector following the fault sectors.

Select embodiments can maintain data throughput by recording the samedata in the fault sectors as that recorded in the consecutive sectorsjust before the fault sectors 83 to 85. In these embodiments, therecording need not be halted temporarily. In a representative embodimentaccording to the present invention, the fault sector numbers can bealready held in the fault sector number checker 82 beforehand, so thedisk I/O protocol circuit 14 can record the same data in fault sectors83-85. The I/O protocol circuit 14 can receive the data from the digitalsignal input circuit 12, and it can record the data in the sectors justbefore the fault sectors 83-85.

Furthermore, in a representative embodiment according to the presentinvention, a disk type recording/reading apparatus can be disposed so asnot to access a fault cylinder that includes fault sectors. Whencompared with a recording operation that skips only fault sectors, therecording operation that can skip a whole cylinder including faultsectors can substantially prevent throughput degradation due to faultsectors. In such embodiments, the record operation can be stopped incylinders in which continuous record operation is usually done.

FIG. 9 is a simplified diagram showing an example arrangement of datarecorded on a hard disk in a still further particular embodimentaccording to the present invention. This diagram is merely anillustration and should not limit the scope of the claims herein. One ofordinary skill in the art would recognize other variations,modifications, and alternatives. FIG. 9 illustrates cylinders 86 to 93in the first area 40. Cylinder numbers 0 to 7 are assigned to thosecylinders 86 to 93. Among cylinders 86 to 93, each of cylinders 3, 4,and 6 includes a fault sector. The fault sector numbers are held in afault sector number checker 82 beforehand, so that the physical sectorcontroller 21 recognizes the numbers of the cylinders that include faultsectors. The fault cylinder numbers recognized by the physical sectorcontroller 21 are thus excluded from the numbering of the continuitysectors, thereby continuous data can be recorded as described above.

In specific embodiments, detecting and skipping fault sector andcylinder numbers can be done in the first area of the hard disk, but itis also possible to perform similar operations on the second and thirdareas. In a representative embodiment according to the presentinvention, continuous data can be recorded by skipping fault sectorsusing the sector RD/WR tester 81 to detect fault sectors on a hard disk,for example. Further, a fault sector number checker 82 can store andrecognize the fault sector numbers. In some embodiments, data throughputcan be improved by recording the same data as that in the sectorspositioned just before the fault sectors into the fault sectorsthemselves, thereby avoiding starts and stops of the recording process.In some specific embodiments, recognizing a cylinder that includes faultsectors and skipping the cylinder can be done to record continuous datain cylinders. Data throughput can be improved in many such embodiments.

Next, further representative embodiments according to the presentinvention will be described with reference to FIG. 10. In a specificembodiment, a data recording apparatus records and reads back datastreams obtained by compressing video and/or audio signals to digitaldata with use of, for example, MPEG or MJPEG encoding on a disk typerecording medium, such as a hard disk.

FIG. 10 is a simplified block diagram of a representative example datarecording apparatus in a yet still further particular embodimentaccording to the present invention. This diagram is merely anillustration and should not limit the scope of the claims herein. One ofordinary skill in the art would recognize other variations,modifications, and alternatives. Many functional blocks in FIG. 10 havebeen discussed previously with reference to FIG. 1. The data recordingapparatus shown in FIG. 10 comprises a video signal input terminal 100and an audio signal input terminal 101. A video signal input circuit 102and an audio signal input circuit 103 can be coupled to video inputterminal 100 and audio input terminal 101, respectively. A videocompression process circuit 104 and an audio compression process circuit105 can be coupled to video input circuit 102 and audio input circuit103, respectively in order to provide compression. Compressed outputs ofvideo compression process circuit 104 and audio compression processcircuit 105 can be coupled into a stream synthesizer 106, for example.The output of stream synthesizer 106 can be provided for storage intothe storage medium. After retrieval, the digital output signal can beinput into a stream separator 113. Stream separator 113 separates thedigital signal input into a compressed video signal output, which can beinput to video expansion circuit 112 and a compressed audio signaloutput, which can be input into an audio expansion circuit 111. Outputfrom audio expansion process circuit 111 and video expansion processcircuit 112 can be provided via an audio terminal 107 and a video signaloutput terminal 108, respectively.

Analog video signals entered from the video signal input terminal 100can be converted to digital video signals and shuffled in the videosignal input circuit 102, for example, then output to the videocompression process circuit 104. The shuffled digital video signals canbe compressed with, for example, MJPEG coding in the video compressionprocess circuit 104, then output to the stream synthesizer 106. In thevideo compression process circuit 104, MJPEG coding may be replaced withanother video compression coding such as the MPEG1 coding, and the like.

In a representative embodiment according to the present invention,analog audio signals can be entered from the audio signal input terminal101, for example. The analog audio signals can be converted to digitalaudio signals and shuffled in the audio signal input circuit 103, thenoutput to the audio compression process circuit 105, for example. Theshuffled digital audio signals are compressed with, for example, theADPCM encoding coding in the audio compression process circuit 105, thenoutput to the stream synthesizer 106. The stream synthesizer 106multiplexes both of the compressed video data and the compressed audiodata at a time axis to data of a single system. The integrated datathrough the time-axis multiplex is entered to the digital signal inputcircuit 12, then recorded on a hard disk continuously.

During read back, the stream separator 113 separates the data outputfrom the digital signal output circuit 15 to compressed video data andcompressed audio data. The video compression process circuit 112 decodesand expands compressed video data and outputs the data to the videosignal output circuit 110. The video signal output circuit 110 thenunshuffles the digital video data so as to be converted to originalanalog video signals and output via the video signal output terminal 24.

The audio expansion process circuit 111 decodes and expands compressedaudio data and outputs the decoded and expanded digital audio data tothe audio signal output circuit 109. The audio signal output circuit 109unshuffles the digital audio data and converts the data to originalanalog audio signals, then output the signals to the audio signal outputterminal 23.

In the representative embodiments described above, video and audiosignals can be compressed to digital signals and treated as continuousdata. Specific embodiments can record both video and audio datacontinuously and read back at random in high quality. In addition,because both recording and reading can be done at the same time, videoand/or audio signals can be read back without stopping the recording ofvideo and/or audio signals.

CONCLUSION

Although the above has generally described the present inventionaccording to specific systems, the present invention has a much broaderrange of applicability. In particular, while foregoing has describedspecific embodiments having a hard disk as a recording, the hard diskmay be replaced with another disk type recording medium, such as anoptical magnetic disk or a phase-change optical disk, and the like bythose of ordinary skill in the art without departing from the scope ofthe presently claimed invention. The specific embodiments describedherein are intended to be merely illustrative and not limiting of themany embodiments, variations, modifications, and alternatives achievableby one of ordinary skill in the art. Thus, it is intended that theforegoing description be given the broadest possible construction and belimited only by the following claims.

The preceding has been a description of the preferred embodiment of theinvention. It will be appreciated that deviations and modifications canbe made without departing from the scope of the invention, which isdefined by the appended claims.

1. A data recording apparatus for recording video data, audio data, or both on a disk-type recording medium, the data recording apparatus comprising: a data recorder operative to record a first digital file including at least one of audio and video data of at least a specified file size sequentially in a first area of said recording medium, and further operative to record a second digital file including at least one of audio and video data of less than the specified file size randomly in a second area of said recording medium, by copying the at least one of audio and video data from said first area while the at least one of audio and video data is recorded in said first area, the first digital file requiring sequential storage in order to ensure a minimum sustained transfer rate; wherein each of said first and second areas on said recording medium comprises a plurality of recording blocks; and wherein said data recorder is operative to record said first digital file in a plurality of physically contiguous sequentially ordered recording blocks in an order of address in said first area and not permit fragmentation or partial erasure of the first digital file in the first area.
 2. A data recording apparatus according to claim 1, wherein: said data recorder is further operative to record management information of data recorded in said first area or said second area in a third area of said recording medium.
 3. A data recording apparatus according to claim 1, wherein: each of the areas on said disk type recording medium is divided in the radial direction of said medium; and said first area is disposed at the outermost portion toward the circumference of said disk type recording medium away from said second area.
 4. A data recording apparatus according to claim 1, wherein: said data recorder records data endlessly in said first area.
 5. A data recording apparatus according to claim 1, wherein: said apparatus further includes a selecting circuit for arbitrarily selecting a starting position and an ending position of data recorded in said first area; and a copying circuit for copying data between said selected starting position and said ending position from said first area to said second area.
 6. A data recording apparatus according to claim 5, wherein: said copying circuit copies data from said first area to said second area while said data recorder records data in said first area.
 7. A data recording apparatus according to claim 2, wherein: said management information comprises numbers of said recording blocks in which said data are recorded.
 8. A data recording apparatus according to claim 2, wherein: said apparatus further includes: a detecting circuit for detecting a fault recording block from said recording medium; and wherein said data recorder records the number of said fault recording block in said third area and skips said fault recording block when recording said data in said first area.
 9. A data recording apparatus according to claim 2, wherein: said apparatus further includes: a detecting circuit for detecting a fault recording track from among tracks formed in a concentric circle pattern on said disk type recording medium; and wherein said data recorder records the number of said fault recording track in said third area and skips said fault recording track when recording said data in said first area.
 10. A data recording apparatus according to claim 2, wherein: said apparatus further includes: a buffering circuit for buffering said continuous data; and a buffer capacity detecting circuit for detecting that data is buffered up to a predetermined capacity in said buffering circuit; and wherein said data recorder records said data in a plurality of recording blocks disposed on a plurality of said tracks formed in a concentric circle pattern on said disk type recording medium according to a result of detection in said buffering capacity detecting circuit.
 11. A data recording apparatus according to claim 10, wherein: the capacity of said buffering circuit is set in tracks on said disk type recording medium.
 12. A data recording apparatus according to claim 1, wherein: said apparatus further includes; means for connecting another additional recording medium to said disk-type recording medium; and means for setting up said first and/or said second areas on said additional recording medium.
 13. A data recording apparatus according to claim 1, wherein said apparatus further includes: means for setting each of said first and second areas to a given size.
 14. A data recording apparatus according to claim 1, wherein: said data is digital data obtained by compressing at least one of video and audio signals; and a frame of video data is recorded at least in not less than one recording block on said recording medium.
 15. A data recording apparatus according to claim 1, wherein: said disk type recording medium is a hard disk.
 16. A data recording apparatus according to claim 1, wherein: said disk type recording medium is an optical magnetic disk.
 17. A data recording apparatus according to claim 1, wherein: said disk type recording medium is a phase-change optical disk.
 18. A data recording apparatus for recording video and/or audio data, comprising: a first disk-type recording medium; a second disk-type recording medium; and a controller configured to: record a first digital file including at least one of audio and video data of at least a specified file size sequentially in a plurality of contiguous sequentially ordered recording blocks continuously arrayed in an order of address in a first area, the first digital file requiring sequential storage in order to ensure a minimum sustained transfer rate, the first area spanning the first disk-type recording medium and the second disk-type recording medium, and record a second digital file including at least one of audio and video data of less than the specified file size randomly in a second area, the second area included in one or more of the first disk-type recording medium and the second disk-type recording medium; wherein said controller is configured to not permit fragmentation or partial erasure of the first digital file in the first area.
 19. The data recording apparatus of claim 18, wherein the first area comprises one or more cylinders spanning the first disk-type recording medium and the second disk-type recording medium.
 20. The data recording apparatus of claim 18, wherein the first disk-type recording medium and the second disk-type recording medium comprise hard disks, optical magnetic disks, or phase-change optical disks.
 21. The data recording apparatus of claim 18, wherein: said data is digital data obtained by compressing video and/or audio signals; and a frame of video data is recorded in at least one recording block in the first area.
 22. The data recording apparatus of claim 18, wherein: the data recorder is further configured to record management information of data recorded in the first area or the second area in a third area, the third area included in the first disk-type recording medium or the second disk-type recording medium. 